Report Created: August 2024
A PurpleAir Classic and a PurpleAir Flex air quality monitoring sensor were installed at a monitoring site in East Hartford, Connecticut to evaluate the sensors performance tracking PM2.5 data. PurpleAir data was corrected using the extended U.S-wide correction equation developed by the EPA to reduce bias in sensor data (more information found here: AirNow). Hourly data from 2023 was then compared to a T640 reference monitor located at the same location. The full dataset used can be downloaded here Download CSV.
Sensor Details
PurpleAir Specifications
| Sensor Type | Cost | Differences | Possible Configuration | Evaluated Configuration | Data Access | Power Supply | Considerations | Reference Monitor Compared |
| PurpleAir Classic | $229 | Micro SD card included | PM2.5, Temperature, Relative Humidity, Pressure | PM2.5, Temperature, Relative Humidity | Micro SD card, WiFi connectivity, API download and live public online map | Potted 5V USB outdoor power supply 12 ft mains plug (purchased separately-$40) |
-Effected by saltwater (issues with coastal use) -Life Expectancy ~2 years |
PM2.5: Teledyne API T640X Temp & RH: AutoMet 580 |
| PurpleAir Flex | $289 | LED viewable with AQI color |
Setup
PurpleAir Classic (left) and PurpleAir Flex (right) air quality monitor.
Timeseries Comparison
PurpleAir Classic and PurpleAir Flex hourly data for PM2.5, temperature and relative humidity were compared by quarter to reference values (Q1: January-March, Q2: April-June, Q3: July-September, Q4: October-December).
PM2.5
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Temperature
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Relative Humidity
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Correlation Comparison
PurpleAir Classic and Reference Correlation
PM2.5
Temperature
Relative Humidity
PurpleAir Flex and Reference Correlation
PM2.5
Temperature
Relative Humidity
PurpleAir Classic and PurpleAir Flex
PM2.5
Temperature
Relative Humidity
Results Summary
